CYANIDE IN APPLE SEEDS
3/15/25
I’ve eaten the entire apple — fruit, skin, core, and seeds — for years without ill effect. Whenever someone sees me do this, they inevitably say something like, “Well, you know, apple seeds contain cyanide,” followed by a cocked eyebrow and maybe a finger wag. Yet, I’m still here. It’s time to look into just how dangerous apple seeds are.
I preface the following by saying I am not a medical doctor and none of this is advice. If you eat apple seeds, get sick and drop dead, it’s your damned fault for listening to some uninformed schlub on the web.
Apples have a five-fold symmetry, with five chambers called carpels. Each carpel usually holds 1 or 2 seeds.
I removed the seeds from the apple and weighed them on a precise analytical scale in our lab. Each seed weighs about 0.07 g, so if an apple has the full 10 seeds, you will consume 0.7 g of seeds.
Apple seeds contain amygdalin, a cyanogenic glycoside, and this is what can cause cyanide poisoning. Many other fruit seeds also have amygdalin, including peaches, plums, apricots, and cherries. I don’t plan to eat any of those. A recent study found that apples contain 1–4 mg of amygdalin per gram of seeds, so the 0.7 g of seeds will in the worst case produce 2.8 mg of amygdalin (Bolarinwa et al. 2015. Determination of amygdalin in apple seeds, fresh apples and processed apple juices. Food Chemistry 170:437–442).
Not all amygdalin gets converted into cyanide; typically, each gram produces 0.06–0.24 mg of cyanide. Again taking the worst case, those ten seeds will make 0.672 mg of cyanide.
Acute cyanide toxicity occurs at doses of 0.5–3.5 mg of cyanide per kilogram of body weight (Speijers, 1993; cited in Bolarinwa et al., 2015). I'm about 72 kilograms, so I could potentially get acute cyanide toxicity if I had 36 mg of cyanide in my system. To get that much, I'd have to eat 54 apples.
Your body can break down small amounts of cyanide; it doesn’t accumulate like other toxins (arsenic, for example). We therefore don’t need to worry about the long-term quantity of apples we eat, but how many we eat over a short period. If I tried to eat 54 apples, I would have other problems to worry about, long before cyanide would be a problem.
All of this assumes the worst case. What if we make the opposite assumptions, that one apple gives us as little cyanide as possible and we are highly resistant to cyanide poisoning? In that case, I would have to eat 12,000 apples to reach toxic levels—about 15 times my body weight!
I’ll keep eating my apples, cores and all. Even if my sweetie gives me a frown.
Postscript: If thinking about cyanide poisoning keeps you up at night, steer clear of improperly processed cassava.